JP6378112B2 - Rotation detection abnormality diagnosis device and method, and rotational position control device using the same - Google Patents

Description

  The present invention relates to a rotation detection abnormality diagnosis device and method and a rotation position control device using the same, and, for example, to a control device for a variable valve timing mechanism that changes the valve timing of an engine valve (intake valve or exhaust valve) of an internal combustion engine. The present invention relates to a device to which the rotation detection abnormality diagnosis device is applied.

For example, in the control apparatus for a variable valve timing mechanism, while detecting a rotational position phase of the cam shaft relative to the crankshaft by the rotation detecting means, by approaching the target rotational phase by the variable valve timing mechanism controls the valve timing.
In Patent Document 1, in a variable valve timing mechanism that drives an intake valve opening / closing camshaft using an electric motor, a rotation signal of a motor shaft that is detected more frequently than the above-described rotation detection means is used. It aims to realize accurate valve timing control in the low speed range.

Japanese Patent No. 4123127

  However, in Patent Document 1, if an abnormality occurs even once in the rotation detecting means at the time of extremely low rotation immediately before starting or stopping the engine, the rotation phase, that is, the valve timing of the intake valve may be erroneously detected. Drive control of the valve timing mechanism is continued due to an erroneous motor operation amount based on the erroneous detection, and the valve timing may greatly overshoot the target value. As a result, engine performance (especially low rotation performance) is impaired, and there is a risk of secondary failure such as a decrease in the durability of the stopper due to the strong contact of the movable part of the valve timing mechanism and the fixing of the movable part to the stopper.

  In addition, the abnormality diagnosis of the conventional rotation detecting means is performed by monitoring the order of the cylinder discrimination values of the cam sensor provided on the camshaft, and since a long period is required until the abnormality is detected after the abnormality occurs, Similar to the above, if an overshoot based on an erroneous motor operation amount occurs, the engine performance is similarly impaired, and there is a possibility that a secondary failure such as a decrease in the durability and adhesion of the stopper may occur.

  The present invention has been made paying attention to such a conventional problem, and when an abnormality occurs in one of two rotation detection means having different detection frequencies, the abnormality can be detected promptly and with high accuracy. An object of the present invention is to make it possible to cope with abnormalities during low rotation.

In order to achieve this object, according to one aspect of the present invention , a crank angle sensor that outputs a crank angle signal in response to rotation of an engine crankshaft and a cam for opening and closing the engine valve are provided. A cam sensor that outputs a cam angle signal in response to rotation of a camshaft that rotates with rotation of the crankshaft, and rotation of the camshaft relative to the crankshaft based on the output of the crank angle sensor and the output of the cam sensor Rotation phase detection means for detecting the phase at predetermined intervals, and a motor shaft rotation angle of an electric motor for rotating the cam shaft relative to the crankshaft is detected at a frequency higher than the detection frequency by the rotation phase detection means. A rotation phase detected by the rotation phase detection means, or the motor rotation sensor is added to the rotation phase. The valve timing is changed by executing feedback control that drives the electric motor so that the value obtained by integrating the amount of change in the rotational phase detected based on the output of the engine approaches the target rotational phase according to the operating state of the engine control apparatus configured variable valve timing mechanism so as to be (and diagnosis method in which), the rotating phase detecting hand stage more detected rotational phase and the amount of change between the previous value, on the basis of the motor change amount of the detected Ru rotation phase based on the output of the rotation sensor to a value obtained by integrating over a predetermined period, one of the abnormality before Kikai rolling phase detecting means and the motor rotation sensor The apparatus further includes an abnormality determining means (step ) for determining the presence or absence of.

The control device for a variable valve timing mechanism, before Symbol abnormality determination means the rotating phase detecting means when the determined to be abnormal rotational phase detected before the rotational phase detecting means is determined to be abnormal The feedback control of the variable valve timing mechanism is continued based on a value obtained by integrating the amount of change in the rotational phase detected based on the output of the motor rotation sensor, and the abnormality determination means indicates that the motor rotation sensor is abnormal. and upon determining the Ru continue to feedback control before Symbol variable valve timing mechanism based on the rotation phase detected by said rotation phase detection means.

According to the control device for a variable valve timing mechanism according to the present invention (and diagnosis method in which), when an abnormality in the rotation phase detecting means or motor rotation sensor is generated, the detection value and the motor rotation sensor of the rotational phase detecting means An abnormality can be detected promptly and with high accuracy on the basis of the detected value based on the output .
Further, according to the control device of the variable valve timing mechanism according to the present invention, when determining the pre-Kikai hand rolling phase detecting means and the motor rotation sensor is abnormal by abnormality determination means, the rotational phase detecting means is detect by is based on the value obtained by integrating the amount of change in the rotational phase detected based on the output of the normal motor rotation sensor to the rotational phase detected before it is determined to be abnormal, or the normal rotational phase detecting means based on the rotation phase, fail-safe operation to continue the feedback control of the variable valve timing mechanism.
Thus, it is possible to suppress the rotational phase of the camshaft is controlled to unfavorable rotational phase overshoots the target rotational phase by abnormal detection detection value.

1 is a system configuration diagram of an internal combustion engine in an embodiment. It is a longitudinal cross-sectional view which shows the variable valve timing mechanism in embodiment. It is a principal part expanded sectional view of the main components in an electric variable valve timing mechanism. It is the sectional view on the AA line of FIG. FIG. 3 is a sectional view taken along line B-B in FIG. 2. It is a disassembled perspective view of the cover member and 1st oil seal which are provided to a variable valve timing mechanism same as the above. It is CC sectional view taken on the line of FIG. It is a figure which shows the structure of the crank angle sensor and cam sensor in embodiment. It is a time chart which shows the output characteristic of the crank angle sensor and cam sensor in an embodiment. It is a perspective view which shows the structure of the motor rotation sensor used for embodiment same as the above. It is a wave form chart of a signal outputted from a motor rotation sensor same as the above, (A) shows the time of the clockwise rotation of the motor, and (B) shows the time of the counterclockwise rotation of the motor. The valve timing is controlled in the embodiment. (A) shows the mirror cycle operation after the start, and (B) shows the valve timing at the start. It is a flowchart of 1st Embodiment which shows the abnormality diagnosis at the time of valve timing control by a variable valve timing mechanism. It is a time chart which shows the change of the various state quantities at the time of valve timing control same as the above. It is a flowchart of 2nd Embodiment which shows the abnormality diagnosis at the time of valve timing control by a variable valve timing mechanism. A part of flowchart of 3rd Embodiment same as the above is shown. A part of flowchart of 3rd Embodiment same as the above is shown. It is a time chart which shows the change of the various state quantities at the time of valve timing control same as the above. It is a time chart which shows the change of the various state quantities at the time of valve timing control same as the above. It is a time chart which shows the change of the various state quantities at the time of valve timing control same as the above.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a configuration diagram of a vehicle internal combustion engine 101 to which a rotation detection abnormality diagnosis device according to the present invention is applied. In the present embodiment, the internal combustion engine 101 is an in-line four-cylinder four-cycle engine, but is not limited to this example.

In FIG. 1, an intake pipe 102 of an internal combustion engine 101 is provided with an electronically controlled throttle 103 that opens and closes a throttle valve 103b by a throttle motor 103a.
The internal combustion engine 101 sucks air into the combustion chamber 106 of each cylinder via the electronic control throttle 103 and the intake valve 105.

  A fuel injection valve 131 is provided in the intake port 130 of each cylinder, and the fuel injection valve 131 is opened by an injection pulse signal from an ECU (engine control unit) 114 as a control device to inject fuel. To do.

  The fuel in the combustion chamber 106 is ignited and burned by spark ignition by the spark plug 104. Each ignition plug 104 is equipped with an ignition module 112 that incorporates an ignition coil and a power transistor that controls energization of the ignition coil.

  The combustion gas in the combustion chamber 106 flows out to the exhaust pipe 111 through the exhaust valve 107. A front catalytic converter 108 and a rear catalytic converter 109 provided in the exhaust pipe 111 purify exhaust flowing through the exhaust pipe 111.

The intake cam shaft 134 and the exhaust cam shaft 110 are integrally provided with a cam, and the intake valve 105 and the exhaust valve 107 are operated by the cam.
The intake valve 105 is variably controlled by a variable valve timing mechanism (electric VTC) 113 that rotates the intake cam shaft 134 relative to the crankshaft 120 using an electric motor (actuator).

  2 to 7, the electric VTC 113 is rotatably supported via a bearing 44 on a timing sprocket 1 that is a driving rotating body that is rotationally driven by a crankshaft 120 of an internal combustion engine, and a cylinder head, An intake camshaft 134 that rotates by the rotational force transmitted from the timing sprocket 1; a cover member 3 that is disposed at a front position of the timing sprocket 1 and is fixed to a chain cover 40 that is a fixing portion by a bolt; The phase changing mechanism 4 is disposed between the timing sprocket 1 and the intake camshaft 134 and is a variable mechanism that changes the relative rotational phase of the both 1, 134 according to the engine operating state. .

  The timing sprocket 1 is integrally formed of an iron-based metal, and an inner peripheral surface is integrally formed on the outer periphery of the sprocket body 1a and an annular sprocket body 1a. And a gear portion 1b that receives a rotational force from the crankshaft via the chain 42. The timing sprocket 1 is interposed between the circular groove 1c formed on the inner peripheral side of the sprocket body 1a and the outer periphery of the thick flange portion 2a provided integrally with the front end portion of the intake camshaft 134. The intake camshaft 134 is rotatably supported by a third ball bearing 43 which is a third bearing mounted.

  An annular protrusion 1e is integrally formed on the outer peripheral edge of the front end portion of the sprocket body 1a. At the front end portion of the sprocket body 1a, there is an annular member 19 that is coaxially positioned on the inner peripheral side of the annular protrusion 1e and has an inner tooth 19a that is a wavy engagement portion formed on the inner periphery. The plate 6 is fastened together by bolts 7 from the axial direction. Further, as shown in FIG. 5, a stopper convex portion 1d, which is an arcuate engagement portion, is formed on a part of the inner peripheral surface of the sprocket body 1a up to a predetermined length range along the circumferential direction. .

  A cylindrical housing 5 that protrudes forward in a state of covering components of a speed reducer 8 and an electric motor 12 described later of the phase changing mechanism 4 is fixed to the outer periphery of the front end side of the plate 6 by bolts 11.

  The housing 5 is integrally formed of an iron-based metal and functions as a yoke. The housing 5 has an annular plate-shaped holding portion 5a integrally on the front end side, and the entire outer peripheral side including the holding portion 5a is The cover member 3 is disposed so as to be covered with a predetermined gap.

  The intake camshaft 134 has two drive cams per cylinder for opening the intake valve 105 on the outer periphery, and the driven member 9 that is a driven rotating body at the front end portion is coupled from the axial direction by the cam bolt 10. Yes. Further, as shown in FIG. 5, the flange portion 2a of the intake camshaft 134 has a stopper groove 2b, which is a locking portion into which the stopper protrusion 1d of the sprocket body 1a is engaged, along the circumferential direction. Is formed. The stopper concave groove 2b is formed in an arc shape having a predetermined length in the circumferential direction, and both end edges of the stopper convex portion 1d rotated in this length range abut against the circumferential opposite edges 2c and 2d, respectively. Thus, the relative rotational position of the intake cam shaft 134 on the maximum advance angle side or the maximum retard angle side with respect to the timing sprocket 1 is regulated.

  The cam bolt 10 is formed integrally with the flange-like seating surface portion 10c on the end edge of the head portion 10a on the shaft portion 10b side, and is formed on the outer periphery of the shaft portion 10b from the end portion of the intake cam shaft 134 to the inner axial direction. A male screw portion that is screwed onto the female screw portion is formed.

  The driven member 9 is integrally formed of an iron-based metal material, and as shown in FIG. 3, a disk portion 9a formed on the front end side, and a cylindrical cylindrical portion 9b formed integrally on the rear end side It is composed of

  The disc portion 9a is integrally provided with an annular step projection 9c having substantially the same outer diameter as that of the flange portion 2a of the intake camshaft 134 at a substantially central position in the radial direction of the rear end surface. The outer peripheral surface of the portion 2 a is inserted and arranged in the inner periphery of the inner ring 43 a of the third ball bearing 43. The outer ring 43b of the third ball bearing 43 is press-fitted and fixed to the inner peripheral surface of the circular groove 1c of the sprocket body 1a.

  Further, as shown in FIGS. 2 to 6, a retainer 41 that holds a plurality of rollers 34 to be described later is integrally provided on the outer peripheral portion of the disc portion 9 a. The cage 41 is formed to protrude from the outer peripheral portion of the disc portion 9a in the same direction as the cylindrical portion 9b, and has a plurality of elongated protrusion portions 41a having predetermined gaps at substantially equal intervals in the circumferential direction. Is formed by.

  As shown in FIG. 2, the cylindrical portion 9 b has a through hole 9 d through which the shaft portion 10 b of the cam bolt 10 is inserted, and a first needle bearing described later which is a first bearing on the outer peripheral side. 30 is provided.

  As shown in FIGS. 2 and 6, the cover member 3 is integrally formed of a relatively thick synthetic resin material and swells in a cup shape, and an outer periphery of the rear end portion of the cover body 3a. And a bracket 3b integrally formed therewith.

  The cover body 3a is disposed so as to cover the front end side of the phase change mechanism 4, that is, to cover almost the entire rear end side from the holding portion 5b in the axial direction of the housing 5 with a predetermined gap. On the other hand, the bracket 3b is formed in a substantially annular shape, and bolt insertion holes 3f are formed through the six boss portions.

  As shown in FIG. 2, the cover member 3 has a bracket 3b fixed to the chain cover 40 via a plurality of bolts 46, and an inner and outer 2 on the inner peripheral surface of the front end 3e of the cover body 3a. Heavy slip rings 48a and 48b are embedded and fixed with their inner end faces exposed. Further, at the upper end portion, there is provided a connector portion 49 in which a connector terminal 49a connected to the slip rings 48a, 48b via a conductive member is fixed. The connector terminal 49a is energized or de-energized from a battery power source (not shown) via the ECU 114.

  A large-diameter first oil seal 50, which is a seal member, is interposed between the inner peripheral surface on the rear end side of the cover body 3a and the outer peripheral surface of the housing 5, as shown in FIG. Has been. The first oil seal 50 is formed in a substantially U-shaped cross section, a core metal is embedded in a synthetic rubber base material, and an annular base portion 50a on the outer peripheral side is formed at the rear end of the cover body 3a. It is fitted and fixed in a circular groove 3d formed on the inner peripheral surface of the part. Further, a seal surface 50b that comes into contact with the outer peripheral surface of the housing 5 is integrally formed on the inner peripheral side of the annular base portion 50a.

  The phase changing mechanism 4 includes an electric motor 12 disposed substantially coaxially on the front end side of the intake camshaft 134, and the speed reducer 8 that reduces the rotational speed of the electric motor 12 and transmits it to the intake camshaft 134. It is configured.

  As shown in FIGS. 2 and 3, the electric motor 12 is a brushed DC motor, and is provided in a housing 5 that is a yoke that rotates integrally with the timing sprocket 1, and is rotatably provided inside the housing 5. A motor shaft 13, which is an output shaft, a pair of semicircular arc permanent magnets 14 and 15 fixed to the inner peripheral surface of the housing 5, a stator 16 fixed to the inner bottom surface side of the housing holding portion 5a, It has.

  The motor shaft 13 is formed in a cylindrical shape and functions as an armature. An iron core rotor 17 having a plurality of poles is fixed to the outer periphery at a substantially central position in the axial direction, and an electromagnetic wave is provided on the outer periphery of the iron core rotor 17. A coil 18 is wound. Further, a commutator 20 is press-fitted and fixed to the outer periphery of the front end portion of the motor shaft 13, and the electromagnetic coil 18 is connected to each segment divided into the same number as the number of poles of the iron core rotor 17. ing.

  As shown in FIG. 7, the stator 16 includes an annular plate-shaped resin holder 22 fixed to the inner bottom wall of the holding portion 5a with four screws 22a, and the resin holder 22 and the holding portion 5a in the axial direction. The first brushes 23a, 23b in the circumferential direction are fed through and are fed in sliding contact with the pair of slip rings 48a, 48b, and inward and backward toward the inner peripheral side of the resin holder 22. The second brushes 24 a and 24 b that are freely held and the arcuate tip end slidably contacts the outer peripheral surface of the commutator 20 are mainly configured.

  The first brushes 23a, 23b and the second brushes 24a, 24b are connected to each other by pigtail harnesses 25a, 25b. Each is biased in the direction.

  The motor shaft 13 includes a needle bearing 28 serving as a first bearing on the outer peripheral surface of the shaft portion 10b on the head 10a side of the cam bolt 10 and a fourth ball bearing serving as a bearing disposed on an axial side portion of the needle bearing 28. 35 is rotatably supported via 35. A cylindrical eccentric shaft portion 30 constituting a part of the speed reducer 8 is integrally provided at the rear end portion of the motor shaft 13 on the intake cam shaft 134 side.

  The first needle bearing 28 includes a cylindrical retainer 28a that is press-fitted into the inner peripheral surface of the eccentric shaft portion 30, and needle rollers 28b that are a plurality of rolling elements that are rotatably held inside the retainer 28a. Has been. The needle roller 28 b rolls on the outer peripheral surface of the cylindrical portion 9 b of the driven member 9.

  In the fourth ball bearing 35, the inner ring 35 a is fixed in a sandwiched state between the front end edge of the cylindrical portion 9 b of the driven member 9 and the seat surface portion 10 c of the cam bolt 10, while the outer ring 35 b is fixed to the inner periphery of the motor shaft 13. Are positioned and supported in the axial direction between the stepped portion formed on the first ring and the snap ring 36 which is a retaining ring.

  A friction member between the outer peripheral surface of the motor shaft 13 (eccentric shaft portion 30) and the inner peripheral surface of the plate 6 is a friction member that prevents leakage of lubricating oil from the inside of the speed reducer 8 into the electric motor 12. Two oil seals 32 are provided. The second oil seal 32 is configured to give a frictional resistance against the rotation of the motor shaft 13 by the inner peripheral portion being in elastic contact with the outer peripheral surface of the motor shaft 13.

  As shown in FIGS. 2 and 3, the speed reducer 8 includes the eccentric shaft portion 30 that performs an eccentric rotational motion, a second ball bearing 33 that is a second bearing provided on the outer periphery of the eccentric shaft portion 30, and The roller 34 provided on the outer periphery of the second ball bearing 33, the retainer 41 that allows the roller 34 to move in the radial direction while retaining the roller 34 in the rolling direction, and the follower integrated with the retainer 41 The member 9 is mainly composed of.

  In the eccentric shaft portion 30, the axis Y of the cam surface formed on the outer peripheral surface is slightly eccentric in the radial direction from the axis X of the motor shaft 13. The second ball bearing 33 and the roller 34 are configured as a planetary meshing portion.

  The second ball bearing 33 is formed in a large diameter, and is disposed so as to substantially overlap at the radial position of the first needle bearing 28, and the inner ring 33 a is press-fitted and fixed to the outer peripheral surface of the eccentric shaft portion 30. The roller 34 is always in contact with the outer peripheral surface of the outer ring 33b. Further, an annular gap C is formed on the outer peripheral side of the outer ring 33b, and the entire second ball bearing 33 can be moved in the radial direction along with the eccentric rotation of the eccentric shaft portion 30 by this gap C. It is possible.

  Each roller 34 is fitted in the inner teeth 19a of the annular member 19 while moving in the radial direction along with the eccentric movement of the second ball bearing 33, and is guided in the circumferential direction by the protrusion 41a of the retainer 41 while having a diameter. It is designed to swing in the direction.

  Lubricating oil is supplied into the reduction gear 8 by lubricating oil supply means. As shown in FIG. 5, the lubricating oil supply means is formed inside a bearing 44 of the cylinder head, and supplies an oil supply passage 47 for supplying lubricating oil from a main oil gallery outside the figure, and the intake camshaft 134. The oil supply hole 48 is formed in the direction of the inner axis of the oil supply passage 47 and communicates with the oil supply passage 47 via the groove groove. The oil supply hole 48 is formed so as to penetrate the oil supply hole 48 in the direction of the inner axis of the driven member 9. A small-diameter oil supply hole 45 whose other end is opened in the vicinity of the first needle bearing 28 and the second ball bearing 33 and three large-diameter oil discharge holes which are also formed through the driven member 9 and which are not shown. And is composed of.

  Hereinafter, the operation of the electric VTC 113 will be described. First, when the crankshaft of the engine is rotationally driven, the timing sprocket 1 is rotated via the timing chain 42, and the rotational force causes the housing 5, the annular member 19, and the plate 6 to rotate. The electric motor 12 rotates synchronously. On the other hand, the rotational force of the annular member 19 is transmitted from the roller 34 to the intake camshaft 134 via the retainer 41 and the driven member 9. Thereby, the cam of the intake cam shaft 134 opens and closes the intake valve.

  When the electric VTC 113 is driven to change the rotational phase of the intake camshaft 134 (valve timing of the intake valve 105), the ECU 114 is energized to the electromagnetic coil 18 of the electric motor 12 via the slip rings 48a and 48b. The As a result, the motor shaft 13 is rotationally driven, and the rotational force of this rotational force is transmitted to the intake cam shaft 134 via the speed reducer 8.

  That is, when the eccentric shaft portion 30 rotates eccentrically with the rotation of the motor shaft 13, each roller 34 is guided by the protrusion 41 a of the retainer 41 in the radial direction for each rotation of the motor shaft 13. The robot moves over the inner teeth 19a while rolling to other adjacent inner teeth 19a, and repeats this in order to make rolling contact in the circumferential direction. The rotational force is transmitted to the driven member 9 while the rotation of the motor shaft 13 is decelerated by the rolling contact of the rollers 34. The reduction ratio at this time can be arbitrarily set according to the number of rollers 34 or the like.

  As a result, the intake camshaft 134 rotates forward and backward relative to the timing sprocket 1 and the relative rotational phase is converted, and the opening / closing timing of the intake valve is controlled to be advanced or retarded.

  The maximum position restriction (angular position restriction) of the forward and reverse relative rotation of the intake camshaft 134 with respect to the timing sprocket 1 is that each side surface of the stopper convex portion 1d is one of the opposing surfaces 2c and 2d of the stopper concave groove 2b. This is done by contacting one side.

  That is, the driven member 9 rotates in the same direction as the rotation direction of the timing sprocket 1 as the eccentric shaft portion 30 rotates eccentrically, so that one side surface of the stopper convex portion 1d is opposed to one side of the stopper groove 2b. A further rotation in the same direction is restricted by contacting the surface 1c. As a result, the relative rotation phase of the intake camshaft 134 with respect to the timing sprocket 1 is changed to the maximum advance side.

  On the other hand, when the driven member 9 rotates in the direction opposite to the rotation direction of the timing sprocket 1, the other side surface of the stopper convex portion 1d abuts against the opposite surface 2d on the other side of the stopper concave groove 2b and further in the same direction. Rotation is regulated. Thereby, the relative rotation phase of the intake camshaft 134 with respect to the timing sprocket 1 is changed to the maximum on the retard side.

  Returning to FIG. 1, the ECU 114 has a built-in microcomputer, performs calculations according to a program stored in advance in a memory, and controls the electronic control throttle 103, the fuel injection valve 131, the ignition module 112, and the like.

  The ECU 114 receives detection signals from various sensors. As various sensors, an accelerator opening sensor 116 that detects an opening (accelerator opening) ACC of an accelerator pedal 116a, an airflow sensor 115 that detects an intake air amount Q of the internal combustion engine 101, and a crank that is an output shaft of the internal combustion engine 101 A crank angle sensor (rotation sensor) 117 that outputs a pulsed rotation signal (unit crank angle signal) POS according to the rotation of the shaft 120, a throttle sensor 118 that detects the opening TVO of the throttle valve 103b, and cooling of the internal combustion engine 101 A water temperature sensor 119 for detecting the water temperature TW, a cam sensor 133 for outputting a pulsed cam signal PHASE in accordance with the rotation of the intake camshaft 134, and a motor rotation sensor for detecting the motor shaft rotation angle of the electric motor for driving the electric VTC 113 201, the driver of the vehicle depresses the brake pedal 121 A brake switch 122 which is turned on in the braking state, is provided with a vehicle speed sensor 123 for detecting a running speed (vehicle speed) VSP of the vehicle to the internal combustion engine 101 as a power source.

  Further, the ECU 114 inputs an on / off signal of an ignition switch 124 that is a main switch for operating / stopping the internal combustion engine 101 and an on / off signal of a starter switch 125.

FIG. 8 shows the structure of the crank angle sensor 117 and the cam sensor 133.
The crank angle sensor 117 is pivotally supported by the crankshaft 120 and has a signal plate 152 provided with a projection 151 as a detected portion around the crankshaft 120 and is fixed to the internal combustion engine 101 side. The crank angle sensor 117 detects the projection 151 and outputs a rotation signal POS. It is comprised with the rotation detection apparatus 153 to output.

  The rotation detection device 153 includes various processing circuits including a waveform generation circuit, a selection circuit, and the like together with a pickup that detects the protrusion 151, and the rotation signal POS output from the rotation detection device 153 is normally at a low level. This is a pulse signal composed of a pulse train that changes to a high level for a certain time when the protrusion 151 is detected.

The protrusions 151 of the signal plate 152 are formed at equal intervals with a crank angle of 10 deg. However, a portion where the two protrusions 151 are continuously removed is sandwiched between the rotation center of the crankshaft 120. It is provided at two opposing locations.
The number of protrusions 151 may be one, or three or more may be continuously deleted.

  With the above structure, the rotation signal POS output from the crank angle sensor 117 (the rotation detection device 153) has continuously changed to a high level 16 times every 10 degrees (unit crank angle) as shown in FIG. After that, the low level is maintained for 30 deg, and then continuously changes to the high level 16 times again.

  Accordingly, the first rotation signal POS after the low level period (tooth missing region, missing portion) having a crank angle of 30 deg is output at intervals of the crank angle of 180 deg. This corresponds to the stroke phase difference between the cylinders in the cylinder engine 101, in other words, the ignition interval.

  Further, in this embodiment, the crank angle sensor 117 uses the piston position at 50 deg before top dead center of each cylinder (BTDC 50 deg.) After the low-level period (tooth loss region) at which the crank angle is 30 deg. It is set to output.

  On the other hand, the cam sensor 133 is pivotally supported at the end of the intake camshaft 134 and is fixed to the internal combustion engine 101 side with a signal plate 158 provided with a projection 157 as a detected portion around it, and detects the projection 157. And a rotation detecting device 159 that outputs a cam signal PHASE.

The rotation detection device 159 includes various processing circuits including a waveform shaping circuit and the like together with a pickup that detects the protrusion 157.
The projections 157 of the signal plate 158 are provided at one, three, four, and two, respectively, at four positions of 90 deg in cam angle. The pitch of 157 is set to 30 deg in crank angle (15 deg in cam angle).

  As shown in FIG. 9, the cam signal PHASE output from the cam sensor 133 (rotation detection device 159) is normally at a low level, and is detected from a pulse train that changes to a high level for a certain time by detecting the protrusion 157. Each pulse signal is changed to a high level with a cam angle of 90 deg and a crank angle of 180 deg.

  In addition, a single cam signal PHASE and a head signal of a plurality of cam signals PHASE that are continuously output are output at an interval of 180 deg at the crank angle, and one single signal, three consecutive, and four consecutive Two consecutive output patterns are output between the top dead center TDC of one cylinder and the top dead center TDC of the next cylinder. It should be noted that even if the valve timing of the intake valve 105 is changed by the electric VTC 113, the cam signal is estimated in consideration of the valve timing change range so that the output position of the cam signal PHASE does not change across the top dead center TDC. The output position and output interval of PHASE are set.

  More specifically, three cam signals PHASE are continuously output between the compression top dead center TDC of the first cylinder and the compression top dead center TDC of the third cylinder, and the compression top dead center TDC of the third cylinder Four cam signals PHASE are continuously output between the compression top dead center TDC of the fourth cylinder, and the cam signal PHASE is output between the compression top dead center TDC of the fourth cylinder and the compression top dead center TDC of the second cylinder. Two signals PHASE are continuously output, and one cam signal PHASE is output between the compression top dead center TDC of the second cylinder and the compression top dead center TDC of the first cylinder. .

  The continuous output number of the cam signal PHASE output between each top dead center TDC indicates the cylinder number that will be the compression top dead center next. For example, between the current top dead center TDC and the previous top dead center TDC. When three cam signals PHASE are continuously output, the current top dead center TDC indicates the compression top dead center TDC of the third cylinder.

  In the four-cylinder engine 101 of the present embodiment, ignition is performed in the order of the first cylinder → the third cylinder → the fourth cylinder → the second cylinder. Therefore, the output pattern of the cam signal PHASE output between the top dead center TDC is As shown in FIG. 3, it is set in the order of single, three continuous, four continuous, and two continuous.

  The ECU 114 determines, for example, the missing position of the rotation signal POS from the periodic change of the rotation signal POS, and counts the number of occurrences of the rotation signal POS with reference to this missing position, thereby obtaining a top dead center TDC (reference Crank angle position) is detected. In the present embodiment, the sixth rotation signal POS output after the missing region of the rotation signal POS corresponds to the top dead center TDC of each cylinder.

  Then, the ECU 114 counts the number of cam signals PHASE output between the top dead centers TDC, thereby determining the cylinder whose piston position will be the compression top dead center TDC (predetermined piston position) and top dead center. The number of occurrences of the rotation signal POS from the TDC is counted, and the crank angle at that time is detected based on the count value CNTPOS.

  When the cylinder and crank angle at the compression top dead center TDC are detected, the ECU 114 determines the cylinder that performs fuel injection and ignition, the fuel injection timing and the ignition timing, and the crankshaft that is detected based on the count value CNTPOS. An injection pulse signal and an ignition control signal are output according to the angle of 120 (crank angle).

  Since the discrimination result of the cylinder whose piston position becomes the compression top dead center TDC (predetermined piston position) is updated in the order of ignition, counting the number of outputs of the cam signal PHASE between the top dead centers TDC. Then, after the cylinder whose piston position is at the compression top dead center TDC (predetermined piston position) is determined, the cylinder at the compression top dead center TDC can be updated for each top dead center TDC in the order of ignition.

  The section for counting the number of occurrences of the cam signal PHASE is not limited to the top dead center TDC, and an arbitrary crank angle (piston position) is used as a reference for the section for counting the number of occurrences of the cam signal PHASE. be able to.

  Further, instead of determining the cylinder at the predetermined piston position based on the number of occurrences of the cam signal PHASE, the cylinder at the predetermined piston position can be determined based on the difference in the pulse width of the cam signal PHASE.

  Further, in the present embodiment, a part of the pulse train of the rotation signal POS is missing, so that the angular position (crank angle) of the crankshaft 120 can be detected based on the missing position, but the rotation signal POS Is output without missing every 10 degrees, and instead, a reference position sensor that generates a signal at a reference crank angle position for every 180 degrees of crank angle is provided, and the rotation signal POS is counted based on the output signal of the reference position sensor. Thus, the angular position (crank angle) of the crankshaft 120 can also be detected.

  In addition, it is changed by the electric VTC 113 by counting the number of occurrences of the rotation signal POS from the reference crank angle position to the single cam signal PHASE or the head signal of the plurality of cam signals PHASE output continuously. The rotational phase of the intake camshaft 134 relative to the crankshaft 120 (the actual valve timing of the intake valve 105) can be detected, and feedback control can be performed so that the valve timing approaches the target value based on this detected value. .

  In addition, the electric VTC 113 includes a motor rotation with a high detection frequency that can detect the rotation angle (rotation operation amount) of a driving electric motor (actuator) as a second driving source including the rotation direction at an arbitrary timing. A sensor (actuator rotation sensor) 201 is provided.

  As shown in FIG. 10, the motor rotation sensor 201 includes a detected portion 201A and a rotation angle detecting portion 201B that is a gap sensor that detects displacement in the rotation direction of the detected portion 201A.

  As shown in FIGS. 2 and 3, the detected part 201A is fitted and fixed to the front end edge of the motor shaft 13, and the rotation angle detecting part 201B is detected by the cover member 3 as shown in FIG. It is fixed by being inserted into a hole formed so as to penetrate a portion facing the front of 201A.

  As shown in FIG. 10, the detected portion 201A is formed in a three-dimensional shape, and three target portions protruding in the axial direction are formed at equal intervals in the circumferential direction. Respectively, an inclined portion 201a having an end face facing the rotation angle detecting portion 201B formed in an arc shape in the circumferential direction, and an edge portion 201b linearly cut from the end edge of the inclined portion 201a in the axial direction and in the radial direction. It is composed of

  Each inclined portion 201a is formed in a downward inclined surface shape at a predetermined angle from one end side with the edge portion 201b at the apex to the other end side in the clockwise direction, and the detection positions by the rotation angle detecting portion 201B are continuous. Changes. On the other hand, each of the edge portions 201b is formed so as to stand up along the radial direction, and is formed in a flat surface shape in the axial direction from one end of the inclined portion 201a, so that the detection position changes discontinuously. .

  The rotation angle detection unit 201B is of an electromagnetic pickup type, and detects a sloped part 201a and an edge part 201b of the opposed part 201A to be detected, thereby forming a continuous step shape (sawtooth shape) as shown in FIG. The waveform signal is output. That is, when the motor shaft 13 rotates in the clockwise direction, the output gradually increases when the inclined portion 201a is detected, and becomes a waveform signal that the output falls sharply when the edge portion 201b is detected (FIG. 11A). Is rotated in the counterclockwise direction, the output gradually decreases when the inclined portion 201a is detected, and becomes a waveform signal whose output rises sharply when the edge portion 201b is detected (FIG. 11B).

  Using this characteristic, when the output gradually increases, the rotation angle of the motor shaft 13 in the clockwise direction (for example, the advance direction) is gradually increased according to the increase of the output, and when the output gradually decreases, the output By gradually increasing the rotation angle of the motor shaft 13 in the counterclockwise direction (for example, the retarded angle direction) in accordance with the gradual decrease of the rotation angle, the rotation angle (rotation operation amount) can be detected continuously (linearly) together with the rotation direction. it can. It should be noted that detection error can be suppressed by learning the output value (output voltage) of the corresponding rotation angle when the edge portion 201b is detected.

  On the other hand, in the internal combustion engine according to the present embodiment, after starting, as shown in FIG. 12 (A), the closing timing (IVC) of the intake valve 105 is largely retarded with respect to the intake bottom dead center (BDC) (or A mirror (Atkinson) cycle operation is performed by setting the valve timing to an advanced angle, and the expansion ratio is made larger than the effective compression ratio of the cylinder. Thereby, knocking avoidance performance is improved and fuel consumption is improved.

  However, if the IVC is retarded (advanced) too much at the time of starting, the cylinder intake air amount decreases and good starting performance cannot be ensured. Therefore, at the time of starting, as shown in FIG. 12 (B), the valve timing control is performed to reduce the retard amount (advance amount) of IVC and approach the BDC, thereby increasing the cylinder intake air amount. The operation will be ensured.

On the other hand, the valve timing of the crank shaft 120 rotates position phase of the intake camshaft 134 relative (first rotating member) (second rotating member), i.e. the intake valve 105 is changed by an electric VTC113 includes a cam signal PHASE from cam sensor 133 Since it is detected for each stroke phase difference between cylinders based on the rotation signal POS from the crank angle sensor 117, the rotation is compared with the control period of the feedback control at the time of extremely low rotation such as at the start (during cranking). The detection period of the phase is long, the detection value is not updated between the previous control timing and the current control timing, and the rotational phase that is changed during this period cannot be detected with high accuracy.

  Therefore, the ECU 114 basically detects the rotational phase of the intake camshaft 134 based on signals from the cam sensor 133 and the crank angle sensor 117 that constitute the rotational phase detection means (first rotation detection means). By using the motor shaft rotation angle detection signal from the motor rotation sensor 201 (second rotation detection means), the valve timing of the intake valve 105 can be detected with high accuracy at an arbitrary timing at the start, and the mirror cycle operation is supported. Advancing control is performed from the valve timing to the valve timing for starting.

  Specifically, first, based on the operating state of the internal combustion engine (the engine that is the first drive source), the VTC target angle, that is, the target rotational phase of the intake camshaft 134 controlled by the electric VTC 113 (the intake valve 105). Target valve timing) is calculated. Here, the VTC target angle is set to the target valve timing for mirror operation shown in FIG. 12A during mirror cycle operation, but at the start time shown in FIG. It is set by switching to the target valve timing.

  Next, the actual VTC angle, that is, the rotational phase of the intake camshaft 134 is detected for each period using the rotational phase detection means, and if detected, the final actual VTC angle is used as the detected actual VTC angle. Ask.

  On the other hand, when the VTC actual angle is not detected by the rotation phase detection means, the relative rotation angle of the intake camshaft 134 with respect to the crankshaft 120 is detected by the motor rotation sensor 201 having a high detection frequency until the next VTC actual angle is detected. As described above, the motor shaft rotation angle (rotation operation amount) of the actuator, that is, the change angle (VTC change angle) of the electric VTC 113 is detected.

  Then, the final VTC actual angle obtained last time is set as an initial value, and the VTC change angle is integrated with this initial value so as to interpolate the period until the next VTC actual angle is detected. An actual VTC actual angle is obtained, and a motor operation amount is calculated such that the VTC actual angle follows the VTC target angle.

  As a result, the electric VTC 113 drives the electric motor 12 according to the motor operation amount, and the valve timing of the intake valve 105 is controlled to the valve timing for mirror operation in which IVC is sufficiently retarded during mirror cycle operation. At the time of starting, control is performed so that the valve timing is advanced for starting.

Here, if an abnormality occurs even once in the rotational phase detection means for detecting the VTC actual angle, there is a possibility that an incorrect VTC actual angle is detected. Further, as described above, the detection cycle is long at the time of extremely low rotation, and the motor operation amount based on the erroneous actual VTC angle is detected until the rotational phase detection means returns to normal and a normal actual VTC angle is detected. By continuing to drive the electric motor 12, the valve timing greatly overshoots the target.
As a result, engine performance (especially low rotational performance) is impaired, and there is a risk that secondary failure such as deterioration in stopper durability and sticking to the stopper due to strong contact of the valve timing mechanism may occur.

  Also, in the conventional abnormality diagnosis of the rotational phase detection means, the order of determining the cylinder at a predetermined piston position based on the cylinder determination value such as the number of occurrences of the cam signal PHASE or the difference in pulse width causes the fuel injection and ignition to be performed. Since it is performed by determining whether or not the order of the cylinders is in accordance, that is, by monitoring the order of the cylinder discrimination values, it takes a long time from the occurrence of the abnormality to the detection of the abnormality.

  Therefore, as described above, until an abnormality of the rotational phase detecting means is detected, an overshoot based on an erroneous motor operation amount occurs, engine performance is impaired, stopper durability is reduced, sticking, etc. Secondary failure may occur.

  Therefore, in the present embodiment, the absolute value of the deviation between the actual VTC angle detected by the rotational phase detection means and the value obtained by integrating the final VTC actual angle detected last time and the VTC change angle detected by the motor rotation sensor 201. By determining that there is an abnormality in the rotational phase detection means when is equal to or greater than a predetermined value, the abnormality in the rotational phase detection means can be detected quickly.

Below, each embodiment of the abnormality diagnosis performed by ECU114 in FIG. 1 is described.
In the present embodiment, when feedback control is performed using the target VTC for starting based on the actual VTC angle detected by the rotation phase detecting means at the time of starting and the VTC change angle detected by the motor rotation sensor 201. Then, abnormality diagnosis is performed based on both detected values.

  Here, since it is difficult to detect the actual VTC angle at the time of non-rotation, the initial value of the actual VTC angle at the time of starting is set according to the feedback control performed during the stop behavior before starting. That is, when feedback control is performed using the target VTC for mirror cycle operation during the stop behavior, it is assumed that the VTC actual angle has converged to the target VTC at the time of stop, and the initial value of the VTC actual angle at the start is set. It is set to the same value as the target VTC for the mirror cycle operation.

  Then, feedback control is started using the initial value of the actual VTC angle and the target VTC that has been advanced for starting. Here, until the VTC actual angle is detected for the first time by the rotational phase detection means, the VTC actual angle is a value obtained by adding the VTC change angle detected by the motor rotation sensor 201 to the initial value (the integrated value of the VTC change angle). ) To perform feedback control. Next, when the VTC actual angle is detected by the rotation phase detection means, the VTC actual angle is replaced with the VTC actual angle detected by the rotation phase detection means from the integrated value of the VTC change angle. Next, the VTC actual angle is updated to a value obtained by integrating the VTC actual angle, and thereafter, every time the VTC actual angle is detected by the rotation phase detecting means, the VTC actual angle is replaced with the detected value while the VTC actual angle is replaced. Accumulated and updated to obtain the final VTC actual angle.

Thus, by using the initial value estimated from the start of the VTC actual angle, the responsiveness at the start can be ensured by the feedback control at the start.
The VTC actual angle detected by the rotation phase detection means and the VTC change angle detected by the motor rotation sensor 201 at the time of extremely low rotation during the stop behavior and the VTC actual angle detected by the motor rotation sensor 201 are used as the target VTC for starting. Feedback control for convergence can also be performed, and the actual VTC angle at the time of starting is brought close to the target VTC for starting, so that the starting performance as good as possible can be obtained from the start of the feedback control.

  On the other hand, the initial value of the VTC actual angle is an estimated value, and it is difficult to ensure sufficient accuracy until the VTC actual angle is detected for the first time by the rotation phase detection means after the feedback control is started. If detection abnormality diagnosis is performed, it is difficult to ensure diagnostic accuracy. Therefore, the abnormality diagnosis is stopped during this period, and the abnormality diagnosis is started after the first actual VTC angle is detected by the rotation phase detecting means.

FIG. 13 shows a flow of the first embodiment.
In step S101, it is determined whether or not the motor rotation sensor 201 is abnormal.
The abnormality diagnosis of the motor rotation sensor 201 is performed by monitoring the sensor output range or the sensor output change amount.

  If it is determined in step S101 that there is an abnormality in the motor rotation sensor 201, the process proceeds to step S107, and the output of the motor operation amount is turned off as fail-safe control when the motor rotation sensor failure is confirmed. Thereby, when there is a failure in the motor rotation sensor 201, the drive of the VTC based on an incorrect motor operation amount can be suppressed.

If it is determined in step S101 that there is no abnormality in the motor rotation sensor 201, the process proceeds to step S102, where the motor rotation sensor 201 calculates a VTC change angle (VAR) per unit time.
In step S103, it is determined whether or not the actual VTC angle is detected by the rotational phase detection means.

If the VTC actual angle is not detected in step S103, the process proceeds to step S106, where the VTC change angle (VAR) calculated in step S102 is added to the previously obtained VTC actual angle (ANGF previous value) to obtain the motor operation amount. The final VTC actual angle (ANGF final value) for calculation is obtained.
ANGF final value = ANGF previous value + VAR

  As a result, even when the detection period by the rotational phase detection means is long and the VTC actual angle is not detected, it is possible to calculate the motor operation amount such that the VTC actual angle follows the VTC target angle, and the drive control of the VTC can be performed. Will continue.

On the other hand, when the VTC actual angle is detected in step S103, the process proceeds to step S104, and as shown in FIG. 14, the VTC actual angle (ANG) and the previously obtained VTC actual angle (ANGF previous value) are set in step S102. It is determined whether or not the absolute value of the deviation from the value obtained by integrating the calculated VTC change angle (VAR) is a predetermined value or more.
| ANG-(ANGF previous value + VAR) | ≧ Predetermined value

  Here, in the conventional feedback control of the valve timing, the VTC change angle calculated by the motor rotation sensor 201 is obtained from the previously obtained VTC actual angle (initial value) in order to remove an error caused by integration with the VTC actual angle. The VTC actual angle in a period in which the VTC actual angle is not detected is interpolated as the change amount of the current VTC. When the current VTC actual angle is detected, the motor operation amount is calculated based on the current VTC actual angle.

However, when an abnormality occurs in the rotational phase detection means, there is a possibility that an incorrect actual VTC angle is detected, and the VTC is driven by a motor operation amount based on this actual VTC angle.
Therefore, after that, until the rotational phase detecting means returns to normal and the normal VTC actual angle is detected, an overshoot due to an erroneous motor operation amount that the VTC actual angle greatly exceeds the target angle occurs. As a result, engine performance is impaired, and there is a risk that secondary failure such as a decrease in durability and sticking of the stopper may occur.

  Therefore, in this embodiment, after confirming that the motor rotation sensor 201 is normal, the absolute value of the deviation becomes equal to or greater than a predetermined value (threshold for abnormality determination) based on the absolute value of the deviation. In this case, the rotational phase detection means is determined to be abnormal.

  As described above, since it is determined in step S101 that there is no abnormality in the motor rotation sensor 201, the VTC change angle (VAR) based on the signal from the motor rotation sensor is obtained by the rotation phase detecting means last time VTC. If the absolute value of the deviation between the value integrated with the actual angle (ANGF previous value) and the VTC actual angle (ANG) detected in step S103 is less than a predetermined value, it is determined that there is no abnormality in the rotational phase detection means. be able to.

  If it is determined in step S104 that the absolute value of the deviation is equal to or greater than the predetermined value, the process proceeds to step S106, and as the fail-safe control when the rotation phase detection means is abnormal, the final VTC actual angle is The VTC change angle (VAR) calculated in step S102 is added to the previously detected VTC actual angle (ANGF previous value).

As a result, the abnormality can be promptly detected and shifted to fail-safe control from when an abnormality occurs in the rotational phase detection means until the actual VTC actual angle is detected until it returns to normal. Drive control can be continued.
As a result, in the feedback control of the valve timing, it is possible to avoid overshooting by avoiding calculation of an incorrect motor operation amount.

In step S104, when the absolute value of the deviation is less than a predetermined value, it is determined that there is no abnormality in the rotational phase detection means.
Thereafter, the process proceeds to step S105, where the final VTC actual angle (ANGF final value) is obtained as the VTC actual angle (ANG) detected in step S103, and feedback control of normal valve timing based on the VTC actual angle is performed.
VTC actual angle (ANGF final value) = VTC actual angle (ANG)

  Next, when the VTC actual angle is not detected by the rotational phase detecting means, in step S106, the final VTC actual angle is changed to the VTC actual angle (ANGF) obtained in step S105, and the VTC change angle ( VAR) is obtained as an integrated value, and feedback control is performed.

According to the first embodiment described above, the abnormality of the rotational phase detecting means is detected quickly by making a comparative determination using the motor rotation sensor 201 having a higher detection frequency than the rotational phase detecting means having a long detection cycle. be able to.
Moreover, since it shifts to fail safe control which continues normal VTC drive control from the time of detecting an abnormality, it is possible to avoid calculating an incorrect motor operation amount in the feedback control of the valve timing, so an overshoot with respect to the target can be avoided. Can be suppressed in advance. Thereby, engine performance is impaired, and it is possible to suppress the occurrence of secondary failures such as a decrease in the durability of the stopper due to the electric VTC 113 and adhesion to the stopper.

FIG. 15 shows a flow of the second embodiment.
In the present embodiment, after confirming that the motor rotation sensor 201 is normal in the first embodiment, abnormality diagnosis of the rotation phase detection means according to the present invention is performed in step S104. After confirming that the motor is normal, the presence / absence of abnormality of the motor rotation sensor 201 is determined by the same abnormality diagnosis method.

The steps different from the first embodiment will be mainly described.
In the present embodiment, the abnormality diagnosis of the motor rotation sensor 201 performed in step S101 of the first embodiment is not performed, and the VTC actual angle is calculated following the calculation of the VTC change angle in steps S201 and S202 as in steps S102 and S103. It is determined whether or not is detected. If the VTC actual angle is not detected in step S202, the process proceeds to step S208, and the VTC change angle is added to the last obtained VTC actual angle (ANGF previous value) in the same manner as the process proceeds from step S103 to S106. The actual VTC actual angle (ANGF final value) is obtained, and the drive control of the VTC is continued.

  Next, in step S203, it is determined whether or not the order of cylinder discrimination is correct based on the above-described abnormality diagnosis of the conventional rotational phase detection means, that is, the cam signal PHASE from the cam sensor 133.

If an abnormality has occurred in the rotational phase detection means, the process proceeds to step S207, and the process shifts to fail-safe control in which the motor operation amount output is turned off and VTC drive control is stopped.
Thereby, the drive of VTC based on the incorrect motor operation amount can be suppressed.

If it is determined in step S203 that there is no abnormality, the process proceeds to step S204, and abnormality diagnosis similar to that in step S104 of the first embodiment is performed.
In this embodiment, since it is determined in step S203 that there is no abnormality in the rotational phase detection means, it is determined in step S204 that there is an abnormality in the motor rotation sensor 201 when the absolute value of the deviation is greater than or equal to a predetermined value. In step S206, the final VTC actual angle (ANGF final value) is obtained as the VTC actual angle (ANG) calculated in step S202.

  That is, when an abnormality occurs in the motor rotation sensor 201, the drive control of the VTC is continued only by the actual VTC angle detected by the rotation angle detection means.

  On the other hand, if it is determined in step S204 that there is no abnormality in the motor rotation sensor 201, the process proceeds to step S205, and similarly to step S105, the VTC actual angle detected in step S203 is set as the final VTC actual angle.

  Unlike the first embodiment, the second embodiment described above confirms that the rotational phase detection means is normal, and then determines the absolute value of the deviation based on the VTC actual angle and the VTC change angle (| ANG-(ANGF previous time). Whether or not the value + VAR) |) is greater than or equal to a predetermined value, that is, whether or not the motor rotation sensor 201 is abnormal is determined by abnormality diagnosis according to the present invention.

16 and 17 show the flow of the third embodiment.
In the third embodiment, when an abnormality occurs in both the rotation phase detection means and the motor rotation sensor 201, that is, the abnormality diagnosis of the rotation phase detection means is performed while taking into account a double failure. The abnormality diagnosis and fail-safe control other than the abnormality diagnosis and various fail-safe controls performed in the second embodiment are also performed.

  In step S301, as in step S203 of the second embodiment, abnormality diagnosis of the rotational phase detection means is performed by monitoring the conventional cylinder discrimination order. If it is determined that there is an abnormality, the process proceeds to step S310 shown in FIG. The abnormality diagnosis of the motor rotation sensor 201 is performed in the same manner as in step S101 in FIG.

  If it is determined in step S310 that there is no abnormality in the motor rotation sensor 201, the process proceeds to step S311 to shift to fail-safe control at the time when the rotation phase detection unit failure is confirmed.

  As the fail-safe control at the time of determining the rotational phase detection unit failure, the VTC change angle (VAR) calculated in step S102 is added to the VTC actual angle (ANGF previous value) obtained last time, as in step S106 of the first embodiment. By integrating and continuing the drive control of the VTC, by limiting the output of the motor operation amount (duty), it is possible to minimize the influence of the fail-safe control on the engine performance.

  In addition, by turning off the output of the motor operation amount or outputting a fixed operation amount for fixing the electric VTC 113 to the fail-safe position (stopper position), the durability of the stopper is reduced and fixed due to an incorrect motor operation amount. Can be suppressed.

  On the other hand, if there is an abnormality in the motor rotation sensor 201 in step S310, that is, if an abnormality has occurred in both the rotation phase detection means and the motor rotation sensor 201, the process proceeds to fail-safe control when a double failure is confirmed.

  In this case, by outputting a fixed operation amount for fixing the VTC at the stopper position, or by turning off the output of the motor operation amount, it is possible to prevent the stopper from being deteriorated and stuck due to an erroneous motor operation amount. .

  Returning to FIG. 16, if it is determined in step S301 that there is no abnormality in the rotational phase detection means, the process proceeds to step S302, and the abnormality diagnosis of the motor rotation sensor 201 is performed in the same manner as in step S101 of the first embodiment. If there is, the process proceeds to step S309 and shifts to fail-safe control when the motor rotation sensor failure is confirmed.

  Here, as fail-safe control at the time of determining the failure of the motor rotation sensor, as in step S107 of the first embodiment, in addition to turning off the output of the motor operation amount, by limiting the output of the motor operation amount, The influence on the engine performance by the fail-safe control can be minimized.

  Further, by outputting a fixed operation amount for fixing the electric VTC 113 at the stopper position, it is possible to suppress a decrease in durability and sticking of the stopper due to an erroneous motor operation amount.

  Further, since it is determined in step S301 that there is no abnormality in the rotational phase detection means, the VTC drive control may be continued only with the actual VTC angle detected by the rotational phase detection means. At this time, since the detection cycle of the final VTC actual angle changes, the control gain used for driving the electric VTC 113 is switched to stabilize the drive control of the VTC, thereby minimizing the influence of the fail-safe control on the engine performance. To the limit.

Further, although it is determined in step S301 that there is no abnormality in the rotation phase detection unit, noise may be detected in the signal output from the rotation phase detection unit.
In this case, since the engine performance is deteriorated and the risk of sticking the stopper is high at extremely low engine speeds, the output of the motor operation amount is turned off.

On the other hand, even if a single abnormality due to noise or the like occurs in the rotational phase detection means, the time for which the drive is continued due to an incorrect motor operation amount is short, and the engine speed is not so high that the engine performance deteriorates and the stopper sticking risk is not so high That is, at the time of high rotation, the drive control of the electric VTC 113 can be continued only with the actual VTC angle detected by the rotation phase detection means.
Thereby, the influence on engine performance by fail safe control can be suppressed to the minimum.

If it is determined in step S302 that there is no abnormality in the motor rotation sensor 201, the process proceeds to step S303.
In steps S303 and S304, as in steps S102 and S103 of the first embodiment, the VTC change angle is calculated (step S303), and it is determined whether or not the VTC actual angle is detected (step S304).

  If the VTC actual angle is not detected in step S304, the process proceeds to step S308, and the final VTC actual angle (ANGF previous value) and the VTC change angle (VAR) are finally determined as in step S106 of the first embodiment. An actual VTC actual angle is obtained, and feedback control of normal valve timing based on the VTC actual angle is performed.

If the VTC actual angle is detected in step S304, the process proceeds to step S305 to perform abnormality diagnosis of the rotational phase detection means according to the present invention.
In this abnormality diagnosis, as described above, the VTC actual angle (ANG) detected in step S304 and the previous VTC actual angle (ANGF previous value) are integrated with the VTC change angle (VAR) calculated in step S303. Whether or not there is an abnormality in the rotational phase detection means may be determined by determining whether or not the absolute value of the deviation from the value is greater than or equal to a predetermined value, but in the third embodiment, other abnormality diagnosis methods Will be described.

  In the third embodiment, the abnormality diagnosis of the rotation phase detecting means is performed by each abnormality diagnosis method described later, but it may be applied to the abnormality diagnosis of the motor rotation sensor 201 performed in step S204 of the second embodiment. .

  For example, as shown in FIG. 18, the change speed (inclination) between the VTC actual angle detected last time and the VTC actual angle detected this time, and a plurality of times from the time when the VTC actual angle was detected to the current detection. A configuration may be adopted in which the presence or absence of an abnormality is determined based on whether or not the absolute value of the deviation from the calculated change rate (slope) of the integrated value of the VTC change angle is equal to or greater than a predetermined value (threshold for abnormality determination).

Further, for example, as shown in FIG. 19, the motor rotation sensor 201 is normal and the VTC is output until the current VTC actual angle is detected until the motor operation amount (duty) is output in the direction in which the VTC actual angle increases. Assume that the angle of change increases.
At this time, there is a case where the actual VTC angle that decreases the angle is erroneously detected this time due to the occurrence of an abnormality in the rotational phase detection means.

  Therefore, the application direction of the motor operation amount (duty) calculated based on the VTC change angle calculated by the motor rotation sensor 201, that is, the relative rotation direction of the intake camshaft 134 with respect to the crankshaft 120 according to the operation amount, and the rotation A configuration may be adopted in which the presence or absence of an abnormality is determined based on whether or not the relative rotation direction of the intake camshaft 134 obtained based on the current VTC actual angle detected by the phase detection means is different.

  In this case, the relative rotation direction of the intake camshaft 134 corresponding to the operation amount does not match the relative rotation direction of the intake camshaft 134 obtained based on the integrated value of the VTC change angle calculated by the motor rotation sensor 201. In such a case, it can be determined that the motor rotation sensor 201 is abnormal.

  Further, for example, when a reference model (internal model for actuator drive control) calculating means for calculating a VTC reference relative angle that changes following a change in the VTC target angle is provided, as shown in FIG. Whether or not there is an abnormality is determined by whether or not the absolute value of the deviation between the VTC reference relative angle (REF) calculated by the calculation means and the VTC actual angle (ANG) detected this time is equal to or greater than a predetermined value (threshold for abnormality determination). It is good also as a structure to determine.

  In this case, when the absolute value of the deviation between the VTC reference relative angle (REF) and the integrated value of the VTC change angle calculated by the motor rotation sensor 201 is equal to or greater than a predetermined value, the motor rotation sensor 201 is abnormal. It can also be determined.

  If it is determined in step S305 that there is no abnormality in the rotational phase detection means by any of the above methods, the process proceeds to step S306, where the final VTC actual angle (ANGF final value) is detected in step S304. Obtained as the actual angle (ANG), feedback control of the normal valve timing based on the actual VTC angle is performed, and when the actual VTC angle is not detected by the rotation phase detection means, the final VTC actual angle is determined in step S308. The VTC change angle (VAR) calculated in step S303 is integrated with the VTC actual angle (ANGF) calculated in step S306, and feedback control is performed.

  On the other hand, if it is determined in step S305 that there is an abnormality in the rotational phase detection means, the process proceeds to step S307, and the process shifts to fail-safe control when an abnormality occurs in the rotational phase detection means.

  As the fail-safe control of step S307, the VTC actual angle (angf previous value) is changed from the final VTC actual angle to the previous VTC actual angle (angf previous value), as in the case of proceeding from step S104 to step S106 of the first embodiment. The normal VTC drive control is continued as an integrated value of VAR), or the fail-safe control such as limiting or turning off the motor operation amount output or outputting the fixed operation amount is performed as in the case of the motor rotation sensor failure determination. You may go.

  Further, fail-safe control at the time of rotational phase detection means abnormality determination, for example, continues VTC drive control (ANGF final value = ANGF previous value + VAR) → motor operation amount in accordance with the increase in the number of abnormality determinations in step S305. The output may be switched step by step so that the output is limited → the output of the fixed operation amount → the output of the motor operation amount is turned off.

  Further, in accordance with an increase in the abnormality determination level (for example, the magnitude of the absolute value of the deviation) in step S305, VTC drive control continues (the absolute value of the deviation is small) → the output limit of the motor operation amount (the absolute value of the deviation) Middle) → The output of the fixed operation amount or the output of the motor operation amount may be switched stepwise such as off (the absolute value of the deviation is large).

  That is, the influence on the engine performance can be suppressed by switching the fail-safe control stepwise in accordance with the number or degree of abnormality determination in step S305.

  In the third embodiment described above, abnormality diagnosis of the rotational phase detecting means is performed in consideration of a double failure in which abnormality occurs in both the rotational phase detecting means and the motor rotational sensor. However, the abnormality is performed in the first and second embodiments. The abnormality diagnosis and various fail-safe controls other than the abnormality diagnosis and various fail-safe controls have been described.

In any of the embodiments, based on the rotation phase detection means and the motor rotation sensor that is detected more frequently than the rotation phase detection means, it is possible to determine the presence or absence of each other and quickly detect the abnormality. If an abnormality is detected, the system shifts to fail-safe control to avoid calculating an incorrect motor operation amount, and to prevent the occurrence of overshoot with respect to the target based on the motor operation amount. be able to.
Thereby, at the time of an extremely low engine speed, engine performance is impaired, and secondary failure such as a decrease in the durability of the stopper due to a strong hit of the valve timing mechanism and sticking to the stopper can be suppressed.

  Further, in the embodiment described above, the abnormality diagnosis is performed at the time of extremely low engine rotation such as at the time of start and at the time of stopping behavior, but the detection cycle by the rotation phase detection means is short at the time of engine high rotation above a predetermined level. Since the possibility that the deviation becomes large is not so high, the abnormality diagnosis according to the present invention may not be performed. Thereby, at the time of high engine rotation, the calculation load can be reduced by abnormality diagnosis.

  Further, in each embodiment, even if it is determined that there is an abnormality in the rotational phase detection means or the motor rotation sensor and the process shifts to various fail-safe controls, the fail-safe control is performed if the normal determination continues by the subsequent abnormality diagnosis. May be released.

  In the above embodiment, the valve timing for the mirror cycle operation of the intake valve and the control for switching between the valve timing for starting is shown, but even in an engine that does not perform the mirror cycle operation, The valve timing for starting can be set optimally.

  Further, in the electric VTC in which the valve timing of the exhaust valve is changed by an electric motor, the present invention can also be applied when the exhaust valve is controlled to a valve timing suitable for starting at the time of starting or stopping.

  In the above embodiment, the rotation detection abnormality diagnosis device according to the present invention is applied to the control device of the variable valve timing mechanism. However, the present invention is not limited to this. A first rotation detecting means for detecting a rotation angle position of a second rotating body that is relatively rotated by the driving source, and a relative change angle of the second rotating body with respect to the first rotating body is detected by the first rotation detecting means. Any device can be applied as long as it includes the second rotation detecting means for detecting at a frequency higher than the frequency.

DESCRIPTION OF SYMBOLS 12 ... Electric motor 13 ... Motor shaft 101 ... Internal combustion engine 105 ... Intake valve 113 ... Electric VTC
114 ... ECU
117 ... Crank angle sensor 133 ... Cam sensor 134 ... Intake cam shaft 201 ... Motor rotation sensor

Claims (11)

A crank angle sensor that outputs a crank angle signal according to the rotation of the crankshaft of the engine ;
A cam sensor provided with a cam for opening and closing the valve of the engine and outputting a cam angle signal according to the rotation of the camshaft that rotates with the rotation of the crankshaft ;
A rotation phase detecting means that detect the rotation phase of the camshaft relative to the crankshaft for each predetermined period based on the output of the cam sensor and the output of the crank angle sensor,
A motor rotation sensor for detecting the motor shaft rotation angle of the electric motor that relatively rotates the cam shaft against the crankshaft at a higher frequency than the detection frequency according to prior Machinery rolling phase detecting means,
The rotation phase detected by the rotation phase detection means, or a value obtained by integrating the rotation phase with a change amount of the rotation phase detected based on the output of the motor rotation sensor, according to the operating state of the engine A control device for a variable valve timing mechanism configured to change the valve timing by executing feedback control for driving the electric motor so as to approach the target rotation phase,
Over Previous Machinery rolling phase detecting means by the detected rotational phase and the amount of change between the previous value, the change amount of the detected Ru rotation phase based on the output of the motor rotation sensor to the predetermined period based on the value obtained by integrating Te, before Kikai rolling phase detecting means and variable valve timing mechanism, characterized in that configured to include the motor further an abnormality determination means to determine the presence or absence of one of the abnormality of the rotation sensor Control device. The abnormality determining means, before Kikai rolling phase function determines the presence or absence of abnormality based on only the output of the cam sensor detection means, and the function determines the presence or absence of abnormality of the motor rotation sensor based on only the output The rotational phase detection means is determined to be normal based only on the output of the cam sensor, and the amount of change between the rotational phase detected by the rotational phase detection means and its previous value, and the motor The presence or absence of abnormality of the motor rotation sensor is determined based on a value obtained by integrating the amount of change of the rotation phase detected based on the output of the rotation sensor over the predetermined period , or the motor rotation sensor is after was decipher the Ru normal der based only on the output, the detected by rotational phase detection means rotational phase and the amount of change between the previous value, based on an output of the motor rotation sensor You determine the presence or absence of abnormality of the rotational phase detecting means on the basis of the variation amount of the rotation phase detected by are in the value obtained by integrating over a predetermined period, the control of the variable valve timing mechanism according to claim 1 apparatus. The abnormality determining means is detected on the basis of prior Machinery rolling phase detecting rotational phase detected by means and the change in the rotational phase velocity determined from the amount of change between the previous value, the output of the motor rotation sensor when the absolute value of the variation amount of the rotation phase difference between the change rate of the rotational phases determined from the value obtained by integrating over a predetermined period is a predetermined value or more, before Kikai rolling phase detecting means and the motor rotation sensor The control device for a variable valve timing mechanism according to claim 1 or 2, comprising a function of determining that one of the two is abnormal. The abnormality determining means, before Kikai rolling phase detecting rotational phase detected by means and the amount of change between the previous value, the variation amount of the rotation phase detected based on the output of the motor rotation sensor wherein when the absolute value of the deviation between the value obtained by integrating over a predetermined period is a predetermined value or more, one of the pre Machinery rolling phase detecting means and the motor rotation sensor comprises a function of determining as abnormal, claim The control device for a variable valve timing mechanism according to any one of claims 1 to 3. The abnormality determination means, that is determined from the variation between the changing direction of the electric motor of the manipulated variable according the rotation phase, before Kikai rolling phase detecting means by the detected rotational phase and its previous value when the change direction of rotation phase is mismatched, function determines that the rotational phase detecting means is abnormal, or a change in direction of the rotational phase corresponding to the operation amount of the electric motor, the motor rotation sensor when the change direction of the that obtained from the value of the variation amount of the rotation phase obtained by integrating over a predetermined period is detected based on the output rotation phase is mismatched, is abnormal the motor rotation sensor The control apparatus of the variable valve timing mechanism according to any one of claims 1 to 4, further comprising a function of determining The abnormality determination means, the absolute value of the difference between the variable valve and Ru are calculated rotation phase according to the internal model for the drive control of the timing mechanism, the rotation phase detected by pre Machinery rolling phase detection means a predetermined A function for determining that the rotational phase detection means is abnormal when the value is equal to or greater than a value, or a rotational phase calculated according to an internal model for drive control of the variable valve timing mechanism, and the motor rotation sensor predetermined absolute value of the deviation between the value obtained by multiplying the previous value of the detected rotational phase of the variation amount of the rotation phase obtained by integrating over a predetermined period value by said rotational phase detecting means is detected based on output The control device for a variable valve timing mechanism according to any one of claims 1 to 5, including a function of determining that the motor rotation sensor is abnormal when the value is equal to or greater than a value. The control apparatus for a variable valve timing mechanism according to any one of claims 1 to 6, wherein the abnormality determination by the abnormality determination means is stopped when the engine speed is high speed or higher. When starting the engine, on the assumption that the pre-start times dislocation phase is converged to set target rotation phase at the time of the feedback control of the previous engine stop behavior in the output of the motor rotation sensor to the target rotational phase feedback control of the variable valve timing mechanism based on the target rotational phase for starting a value obtained by integrating the variation amount of the rotation phase of the detection is started based on,
The abnormality determination means performs an abnormality determination from the after Rikai transposition phase was first detected by the rotational phase detecting means, the control of the variable valve timing mechanism according to any one of claims 1 to 7 apparatus. When the previous SL abnormality determination means determines that said rotating phase detecting means abnormality is detected based on the output of the motor rotation sensor to the rotational phase detected before the rotational phase detecting means is determined to be abnormal The feedback control of the variable valve timing mechanism is continued based on a value obtained by integrating the amount of change in rotational phase, and detected by the rotational phase detection means when the abnormality determination means determines that the motor rotation sensor is abnormal. continuing the feedback control of the pre-Symbol variable valve timing mechanism based on the rotational phase of the control device of the variable valve timing mechanism according to any one of claims 1 to 8. When the abnormality determination unit determines that the rotation phase detection unit is abnormal, the motor rotation is rotated to a rotation phase detected before the rotation phase detection unit is determined to be abnormal in response to an increase in the number of abnormality determinations. Continue feedback control of the variable valve timing mechanism based on a value obtained by integrating the amount of change in rotational phase detected based on the output of the sensor, and change the valve timing to the maximum advance side or the maximum retard side. The variable valve timing mechanism according to any one of claims 1 to 9, wherein the switching is performed in order of driving the electric motor and stopping the output of the operation amount for driving the electric motor. Control device. A crank angle sensor that outputs a crank angle signal as the crankshaft of the engine rotates ,
A cam sensor provided with a cam for opening and closing the valve of the engine and outputting a cam angle signal with rotation of the camshaft rotating with rotation of the crankshaft ;
A rotation phase detecting means that detect the rotation phase of the camshaft relative to the crankshaft for each predetermined period based on the output of the cam sensor and the output of the crank angle sensor,
A motor rotation sensor for detecting the motor shaft rotation angle of the electric motor that relatively rotates the camshaft relative to the crankshaft at a higher frequency than the detection frequency according to prior Machinery rolling phase detecting means,
The rotation phase detected by the rotation phase detection means, or a value obtained by integrating the rotation phase with a change amount of the rotation phase detected based on the output of the motor rotation sensor, according to the operating state of the engine An abnormality diagnosis method in a control device for a variable valve timing mechanism configured to be able to change valve timing by executing feedback control for driving the electric motor so as to approach the target rotation phase,
Over Previous Machinery rolling phase detecting means by the detected rotational phase and the amount of change between the previous value, the change amount of the detected Ru rotation phase based on the output of the motor rotation sensor to the predetermined period based on the value obtained by integrating, to determine the presence or absence of one of the abnormality before Kikai rolling phase detecting means and the motor rotation sensor that Te,
Abnormal diagnostic how to characterized in that it comprises a.